The products will demonstrate their glow-in-the-dark characteristics after about 5-10 minutes of light exposure. With about 2 hours of exposure to sunlight they will glow for about 10-12 hours of darkness. Below is a chart that demonstrates the product’s typical performance.

GLOW Stones USA products last about 20 years.

This data was compiled using laboratory tests to determine the strength of the glow. Please note that the glow does diminish with time. A noticeable change in glow strength will be seen within 60 minutes.